Question

find the length of the radius of circle c.
http://media.education2020.com/evresources/2092539_2f57b746-c73f-4a4b-8c7e-ce9ee207b927.png

Answer 1

A.
r=1
B.
r=3
C.
r=12
D.
r=15

Answer 2

@dan815

Answer 3

@DanJS

Answer 4

okay that angle you see is actually in radians

Answer 5

when they say 4/9 pi they really mean 4/9 pi radius is our angle

Answer 6

that means this angle you see subtends a total of 4/9 pi radius units on the circumference of the circle

Answer 7

\[\frac{4}{9}\pi * r =\frac{20}{3} \pi \]\

Answer 8

ohh

Answer 9

yep :) so what is r

Answer 10

so it would be r=15

Answer 11

yep

Answer 12

Thank you soo much

Answer 13

arc length = radius* theta

Answer 14

:)

Answer 15

dont let radians confuse you, its a very simple idea, we are saying the angle in terms of the radius units
thats why there are 2pi radians in a circle beacuse the circumference of a circle is 2 pi r

Answer 16

ok thank you.:)

Answer 17

welcome

Answer 18

yeah , i was looking for a easy explination that @dan815 just said...
http://www.themathpage.com/atrig/arc-length.htm